code: def unset_sub_backend(sub_backend_str: str):
      if sub_backend_str not in ivy.current_sub_backends:
          return
      global original_backend_dict
  
      # The sub-backend is cached so this is fast
      sub_backend = importlib.import_module(
          _sub_backend_dict[sub_backend_str]
      )
      _unset_sub_backend_from_ivy(
          original_backend_dict, ivy, sub_backend, sub_backend.name
      )
      ivy.current_sub_backends.remove(sub_backend_str)
  
file_path: ivy/ivy/utils/backend/sub_backend_handler.py
imports: import os
  import re
  from types import ModuleType, FunctionType
  import logging
  import importlib
  import ivy
  from ivy.func_wrapper import _wrap_function
  from ivy.utils.exceptions import IvyException
label_desc: Use image node_id 6 for calling a global function with example usage: unset_sub_backend(sub_backend_str) without return types